Acoustic device



Feb. 9, 1937. H. R. CLARKE ACOUSTIC DEVICE Filed Sept. 26, 1933 v w V I mnmn lNl EN TOR H. R. CLARKE 04am 6. m

'AT'TORNEK Patented Feb. 9, 1937 STATES ATE OFFICE ACOUSTIC DEVICE Application September 26, 1933, Serial No. 691,015

3 Claims.

This invention relates to acoustic devices and, more particularly, to sound wave reproducers or receivers of the type employed in systemsor apparatus for aiding the hearing.

An object of this invention is to facilitate the assembly and disassembly of the magnet structure of a sound wave reproducer.

Another object is to enable proper polarizing of a sound wave reproducer of the electromagnetic type.

A feature of this invention comprises a sound wave reproducer or receiver having a magnet structure retained securely within a case by a unitary, readily detachable member.

A further feature comprises a sound wave reproducer or receiver having terminal members within its case and passages for conductor ends or cord tips leading thereto, the passages being of dissimilar characters or configurations.

This invention is embodied, preferably, in a telephone receiver comprising a case of insulating material having a central, cylindrical recess, an annular portion of which at its open end is interiorly threaded. Pole pieces, preferably L- shaped and having their horizontal portions resting in channels at the bottom of the recess, and a magnet, preferably annular and partly in an annular recess in the bottom of the recess and partly on the horizontal portions of the pole pieces, are retained in position in the recess by a magnet securing or retaining means. This means, preferably, comprises an annular member resting on the upper surface of the magnet and having a depending flange, exteriorly threaded for engagement with the threaded portion of the recess wall. Terminal members, preferably embedded in the case, are connected to an energizing winding surrounding the vertical portions of the pole pieces. The case contains cord tip passages leading to the terminals, one passage, preferably, being square and the other round. A diaphragm unit is clamped against the case rim and held in place by a cap or earpiece member.

A more complete understanding of this invention will be obtained from the detailed description which follows, read with reference to the appended drawing, wherein:

Fig. 1 is a plan view, partly broken away, of a telephone receiver embodying this invention;

Fig. 2 is a sectional view of the device of Fig. 1 along the line 22 thereof;

Fig. 3 is a sectional view of the device of Fig. 1 along the line 3-3 thereof;

Fig. 4 is a perspective view, partly broken away and partly in section, of the case of the device of Fig. 1;

Fig. 5 is an elevational view of the device of Fig. 1 showing its cord tip passages; and

Fig. 6 is a perspective view of the cord tips of the conductor cord for the device of Fig. 1.

The acoustic device shown in the drawing'is a telephone receiver comprising a case Ill, preferably of an insulating material, having a central, cylindrical recess ll, an annular portion l2 of which at its open end is interiorly threaded. Pole pieces I 3, preferably L-shaped and of silicon steel, have their horizontal portions or legs I l resting in radially extending, oppositely disposed channels at the bottom of the recess II and their ver tical portions or legs 16 surrounded by the energizing coils 11. An imperforate permanent magnet l8, preferably annular, of rectangular section, and of slightly smaller external diameter than the diameter of the recess extends slightlyinto annular channel IS in the bottom of the recess and rests on the ends of the portions 14 of the pole pieces 13. The magnet and pole pieces are retained securely in position in the recess and in contact with one another by a magnet retaining or securing member, designated generally as 20. member 20 comprises an annulus or planar portion 2! resting on the upper surface 22 of the magnet and having a depending flange 23, exteriorly threaded at 24 for engagement with the interiorly threaded annulus l2 of the recess. Facile assembly and disassembly of the magnet structure of the receiver is thus possible; and the magnet and pole pieces are maintained in positive engagement. The apertures 25 in the annulus 2i are provided so that the threading of the member 23 into or out of the recess may be accomplished with an appropriate tool (not shown).

A diaphragm unit, designated generally as 26, is supported on the rim 27 of the case, being clamped thereagainst by a receiver cap or earpiece 28 which threadedly engages with the case. The diaphragm unit comprises a pair of annular plate members 29, 38, preferably riveted together at their peripheries, and enclosing a diaphragm 3i and a plurality of paper damping washers 32, the diaphragm and washers being supported by the plate 29 and disposed in a recess 33 in th plate 30.

Terminal members 34, preferably embedded in the case, are connected at their upper extremities to the end of the energizing coils by wires 35. The case contains passages 36, 31 of dissimilar configurations to receive the ends or tips of the conductors of the receiver cord. The passage 36 is circular and is adapted to receive a cylindrical shaped cord tip 38' of a conductor 39,. andthe .means for actuating said diaphragm including V L-shaped pole-pieces and apermanent magnet,

passage 3'lis rectangular ,andis adapted to" receive a cord tip 40 of a conductor 4| which is of a rectangular section. The cordtips are held in the passages 36, 3'! by set screws 42 (one only be-' ing shown) which thread through the terminal members and clamp thecord tips againstthe passage walls. The passage .43 is for a stay cord.

The cord tips. .and cord tip passages are given.

dissimilar configurations so that the conductors of the cord 44 may be cperatively con'nectd'to the receiver in one Way only, and without any instruction to or skill on the part of the user required. At all times} therefore, the receiver; will be properly polarized and the receiver and cord may bedisconnected from one anOtherWithout fear that in reconnecting the conductors will be incorrectly attached.

While. the features of this invention have been disclosed in a specific structure, it is understood, of course, that various modifications vmay be made in the details of construction without departing from the scope of the invention as defined in the'appended claims.

What'is claimed is: Y r V 1. An acoustic device comprising a diaphragm,

means for actuating the diaphragm, said means comprising a pair of L-shaped pole pieces, an energizing winding on the vertical portions of said pole pieces, an annular permanent magnet resting on the horizontal portionof said pole pieces,

a case for said diaphragm and containing a re- .cess for said means, and a unitary'member comprising an annular portion anda peripheral flange portion, the annular. portion resting on the mag net'and the peripheral portion engaging the wall r of the recess to retain the actuating means in said recess, said unitary member being movableindependently of-saidjactuating means and'consti a case for said diaphragm and means, said case having an open end provided with an internally threaded portion, and having an oppositely dis posed closed end with radially extending recesses V on its inner surface to receive the horizontal por- 10 tions of said pole-pieces, and a recess crossing the radial recesses-to receive the magnet for engagement'with the pole-piece horizontal portions,.and means for clampingsaid magnet andpole-pieces together'and securing them against movement in 15- said case, said clamping means comprising 'a planarmember resting on the surface of the magnetopposite'that' engaging the pole-pieces, and

having a peripheral portion depending toward said pole-pieces and externally threaded to engage 20 said internally threaded open end of the case.

.3. A telephone receiver comprising a diaphragm, V

means for actuating said diaphragm including- L-shaped pole-pieces .and a permanent magnet,

a ca'seforsaid diaphragm and means, said casea25 having aniopen end provided with an internally threaded portion, and having an oppositely. dis,- posed closed end with radially extending recesses on its inner surface to receive, the horizontal portions of said pole-piec'eaand a recess crossing ther' 30 radial recesses to receive the magnet for engage+ ment with the pole-piece horizontal portions, and means for clamping said magnet and pole-pieces together and securing them against movement in said case, said clamping meanscomprising a 35 planarmember' resting on, the surface of the ma'gnet opposite that engaging the pole-pieces, and having a peripheral portion externally threaded. to engage said internally threaded open end of the case; '1 V .HARRYR. CLARKE. 

